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(No Model.) Sheets-Sheet 1.

C. E. SCRIBNBR. y KEYBOARD APPARATUS FR TELEPHONE SWI'IGHBOARDS.

No. 564,453. Patented July 21, 18961 (No-Model.) 2 Sheets-Sheet 2 C. E. SCR-IBNBR. KEYBOARD APBARATUS PoR TELFPH0N.T;s WITGHBofmDs.v

No. 564,458. Patented July 21, 1896f UNITED STATES PATENT OFFICE.

CHARLES E. SORIBNER, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE VESTERN ELECTRIC COMPANY, OF SAME PLAOErV KEYBOARD APPARATUS FOR TELEPHONE-SWITCHBOARDS.

SPECIFICATION forming part ef Lettere Patent No. 564,458,01eted :rely 21,1896. Appiieetion filed Mey 14,1894. seriei No. 511,206, (No model.)

To all whom t nfl/ty concern,.-

Be it known that I, CHARLES E. SCRIBNER,

a citizen of the United States, residing at Ohicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Keyboard Apparatus for Telephone-Switchboards, (Case No. 351,) of which the following is a full, clear, concise, and exact description, reference being had to 1o the accompanying drawings, forming a part of this specification.

My invention relates to the connecting appliances or operators keyboard apparatus upon telephone-switchboards. Its object is to simplify the circuits and reduce the number of keys to be manipulated bythe operator. Hitherto it has been customary to provide two keys in each plug-circuit orpair of conductors uniting the members of a pair of connecting-plugs, one key for' transmitting signaling-current to each of the connected substations independent of the other. It has been found in practice, however, that it is but rarely necessary to send a signaling-current to the substation of the call-initiating subscriber, and that it is sufficient to provide a single key for each operator for signaling to the calling subscriber. t

My invention consists in the combination, with the operators listening-key adapted to close a bridge-circ'uitbetween the different conductors of the plug-circuit, of a signalingkey included in this conductorarranged to connect the operators telephone or a generator of signaling-current alternately intoithe circuit of this conductor. Each plug-circuit is provided with a separate listening-key, the conductor which connects with the plug-circuits being common to all of the keys, but 4o only a single signaling-key is provided in this conductor, and a single telephone and signaling-generator are controlled by this key. One signaling-key only is provided in each plugcircuit, arranged, as usual, to transmit signaling-current to that plug which is designed to be used in connecting with the line called for. Using this apparatus, the operator may signal to the line called for, or the answeringline,7 by depressing the signaling-key in the 5o corresponding plug-circuit; but if it should be necessary to signal to the calling subscriber she may do this by depressing the comm on signaling-key,thereby disconnecting her telephone from the plug-circuit and connecting the signaling-generator in a bridge between the sides of the plug-circuit and signaling both subscribers.

My invention is especially adapted for use with an improved combined listening and callingkey, which I have described in a joint 6o application with Frank R. McBerty, (Case No. 346,) filed January 10,1894, Serial No. 496,443.

My invention is illustrated in the accompanying drawings, being shown in connection with'the combined listening and ringing key mentioned.

Of the drawings, Figure l is a plan view of the combined key, Fig. 2 being a longitudinal sectional view of the same, and Fig. 3 a view 7o from beneath showing the disposition of the circuit-controlling springs. Fig. 4 is a diagram representing the circuit connections of the entire plug-circuit and showing the connection of my new common signaling-key therewith, the plug-circuit being represented in a position of connecting two telephone-lines together upon a telephone-switchboard.

Referring to Figs. l, 2, and 3, the combined listening and calling key will be seen to con- 8o sist of a pair of buttons ct a', acting upon opposite extremities of a centrally-pivoted lever b, which carries a double-faced wedge or cylinder c, moving between the presented extremities of four switch-springsd CZ d2 d3. The 85 springs CZ, cl2, and d3 are each provided with a normal resting contact-'anvil e, e2, and e3, respectively, and with alternate contact-anvils f, f2, and f3, respectively. The spring d/ has no normal resting contact but has an alternate 9o contact f. It controls a spring g to retain it normally separated from a 'resting contact 71,. When either button isl depressed, the wedge c is forced between the oppositely-disposed pair of switch-springs, separating them from their normal resting contacts and forcing them outward against their alternate contacts.

In Fig. 4 the springs d and d2 of the combined listening and ringing key t' are seen to be connected with the tips of two plugs la and roo k', respectively, while the switch-springs d and da are connected with the sleeves of the same plugs. The resting contacts e2 e3 of springs d2 d3 are connected by wires l and 2 with the tip and sleeve, respectively, of the plug k, whereby the like parts of the two plugs of the pair are united. The alternate contacts f2 and f3 of springs cl2 and d3 constitute the terminals of a generator Z of signalingcurrent suitable to operate the signal-bells at the subscribers stations. Thus, when by depressing button a the wedge c is forcedbetween switch-sprin gs cl2 and d3, the plug 7e is disconnected from its mate and the signalinggenerator Z is looped into circuit between its contact-pieces to transmit a si gnaling-current over the telephone-line into a spring-jack of which plug 7.a is inserted.

The alternate contacts j' and j" of springs d and d' are connected with the switch-sprin gs m and m of the common signaling-key n. The resting contacts m2 and m3 of these switchsprings constitute the terminals of the operators telephone o, while their alternate contacts m4 and m5 are connected with the poles of the signaling-generator Z. Hence, when the button a is depressed, a bridge-circuit is formed between the conductors uniting the like parts of the two plugs, which normally includes the operators telephone o, but into which the signaling-generator Z maybe introduced by the depression of the plunger 1J.

A clearing-out annunciator q has its main or operating magnet included in a bridge between' the different conductors of the plugcircuit, together with the contact-anvil e, by which its circuit is opened when the operators telephone is introduced.

A local circuit, including a battery r, is provided for resetting the clearing-out annuciator q, being controlled by contact-points g h of the key t', by which the circuit is closed to reset the indicator of the annunciator when the operators telephone is connected with the plug-circuit.

In Fig. 4: the plugs k and 7d, wit-h their uniting conductors, are shown in position of connecting two telephone-lines together. The subscribers lines represented are of the usual character. Each substation is provided with signaling and telephonie apparatus connected by line-wires s s and s2 s3, respectively, with spring-jacks t and t', t2 and t3, upon a switchboard in a telephone-exchange, and also with annunciators u and u upon the switchboard. Each spring-jack has two contact-pieces v and e', which are connected with the line-wires, respectively, and which are arranged to register with the tip and sleeve of au inserted connecting-plug, and two local contact-pieces U2 t3, which represent the normally-separated terminals of the local resetting or restoring circuit of the annunciator. These latter contact-pieces are arranged to be crossed together by an insulated metallic ring upon the connectin g-plug when the latter is inserted in the spring-jack. A test-ring fc4 is also provided upon each spring-jack, connected with the spring r2, whereby it is electrified by connection with the grounded restoring-battery w when connection is made with the spring-jack, together with the similar pieces of all the other spring-jacks belonging to the same line, since the test-rings are electrically connected together. The spring-jacks tand t may be assumed to be located upon two different sections a: and of a multiple switchboard and the annunciator u upon the section w. The spring-jacks t2 and t3 of the other subscribers line are likewise located upon the sections and a-, respectively.

In the operation of this apparatus the subscriber transmits a calling-signal by operating his signaling-gen erator in the usual manner. rihe signaling-current iinds circuit through the annunciator u and discloses the indicator thereof` The attendant operatorat board m', seeing this signal, inserts the plug k into spring-jack t of the corresponding line upon her section of switchboard, whereby her telephone o is connected with the line-wires s s through the switch-springs d CZ and their anvils ff of the listening-key t, it being understood that the listening-key is left, when out of use, with the wedge c forced between springs CZ d. Having received the order for connection with the desired line, the operator tests the spring-jack i3 of the required line upon her switchboard by applying the tip of plug k to the test-ring fut of the jack. Il' another connection already exists with the corresponding line, the electriiication of this test-ring will produce a current through the tip of the plug and the conductor connected therewith, through switch-spring cl2 and its anvil e2, and thence through one-half of the operators telephone o to earth in the usual way, creating a click in the telephone and thus indicating to the operator that the line is already in use. Assuming, however, that it be found-idle, she inserts the plug 7o fully into the spring-jack t3, thus electrically uniting the apparatus of the two substations through a complete metallic circuit. rlhe operator. then depresses button ct of key t', whereby the springs d2 d3 are separated from their anvils and are closed upon the terminals of generator Z, transmitting a signaling-current to the substation with whose line connection has been established. When the button ct is released, the wedge c is returned, by the pressure of springs cl2 d3, to its central position, the telephone being then disconnected, since the springs d cl are disengaged from their anvils f f. If, however, it should be necessary to signal to the call-initiating subscriber to indicate that the desired connection has been completed, asin case the line called for was not immediately accessible, the 0perator would depress the plunger p of the cornmon key n, the keyt' of the plug-circuit in use being still in position of connecting her telephone with the plug-circuit. By this means the generator Z would be connected in a bridge between the conductors of the plug-circuit in place of telephone o, and would transmit sig- ICO IIO

564,458 l aA naling-current to both of the connected substations. The operator would then depress the button a sufficiently far to bring the Wedge c to its intermediate position between the switch springs, permitting springs d d to separate from their anvils ff', but not forcing the springs d2 cl3 outward upon their contact-anvils f2 f3, thus disconnecting her telephone. v

Having thus described my invention, I claiin as new and desire to secure by Letters Patent- 1. The combination with several pairs of connecting-plugs, of a separate key for each pair of plugs adapted to connect the different conductors of the corresponding plug-circuit together through a bridge conductor common to the different keys Without interrupting the continuity of the plug-circuit, and a signaling-key adapted to loop a generator of signaling-current into the said common bridge conductor, substantially as described.

2. The combination'with several pairs of connecting-plugs, each pair being united by conductors constituting a plug-circuit, of a key for each pair of plugs adapted to 'complete a bridge connectionA between the different conductors of the corresponding plug-cir-` cuit through a conductor common to all of the said keys Without interrupting the plugcircuit, and another key controlling the said common conductor, adapted to include the operators telephone or a source of signalingcurrent alternately into the common bridge conductor, substantially as described.

3. The combination With several pairs of connecting-plugs, the members of each pair being united through conductors constituting a plu g-circut, of a signaling-key in each plugcircuit adapted to disconnect the contactpieces of one plug of the pair from those of the other member of the pair and to connect them with a generator of signaling-current, a listening-key in each plug-circuit adapted to unite the different conductors of the corresponding plug-circuit through a bridge conductor common to all the listening-keys, and a key included in said bridge conductor adapted to loop an operators telephone or a generator of signaling-current alternately into the bridge conductor, substantially as described.

In Witness whereof I hereunto subscribe my name this 9th day of April, A. D. 1894:.

CHARLES E. SCRIBNER.

Vitnesses:

ELLA EDLER, LUcrLE RUSSELL. 

